Display substrate, manufacturing method thereof, and display panel

ABSTRACT

A display substrate may include a base substrate (10), a plurality of sub-pixels (20) in an array on the base substrate (10), an isolation layer (30) on a side of a second electrode layer (123) opposite from the light-emitting layer (22), and an auxiliary conductive layer (40) on a side of the isolation layer (30) opposite from the second electrode layer (123). The isolation layer (30) may comprise at least two via holes (31), orthographic projection of each of the at least two via holes (31) on the base substrate (10) may substantially overlap with orthographic projection of the pixel defining layer on the base substrate (10), and the auxiliary conductive layer (40) may be connected to the second electrode layer (123) through the at least two via holes (31).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of the filing date of Chinese PatentApplication No. 201910023876.0 filed on Jan. 10, 2019, the disclosure ofwhich is hereby incorporated in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to the field of display technology, andin particular, to a display substrate, a method of manufacturing thedisplay substrate, and a display apparatus.

BACKGROUND

An organic light emitting diode (OLED) display panel in related artincludes sub-pixels distributed in an array, wherein each sub-pixelincludes a light-emitting layer, an anode under the light-emittinglayer, and a cathode on the light-emitting layer. Cathodes of therespective sub-pixels are connected to one another to form an integralcathode layer. A driving circuit is connected to the cathode layer toprovide a cathode voltage for the cathode layer (ie, the cathode of eachsub-pixel).

BRIEF SUMMARY

One embodiment of the present disclosure provides a display substrate.The display substrate may include a base substrate; a plurality ofsub-pixels in an array on the base substrate, wherein adjacentsub-pixels are separated by a pixel defining layer, each of theplurality of sub-pixels includes a first electrode, a light-emittinglayer and a second electrode in a direction away from the basesubstrate, the second electrode of each of the plurality of sub-pixelsis connected to one another to form a second electrode layer; anisolation layer on a side of the second electrode layer opposite fromthe light-emitting layer; and an auxiliary conductive layer on a side ofthe isolation layer opposite from the second electrode layer. Theisolation layer comprises at least two via holes, orthographicprojection of each of the at least two via holes on the base substratesubstantially overlaps with orthographic projection of the pixeldefining layer on the base substrate, and the auxiliary conductive layeris connected to the second electrode layer through the at least two viaholes.

Optionally, a thickness of the isolation layer is in a range from about10 nm to about 90 nm.

Optionally, the at least two via holes comprises a plurality of viaholes within some of intervals among the plurality of sub-pixels,respectively.

Optionally, the at least two via holes comprises a plurality of viaholes within all of intervals among the plurality of sub-pixels,respectively, and all of the intervals among the plurality of sub-pixelsin a first direction are the same.

Optionally, the plurality of sub-pixels constitutes a plurality ofpixels, intervals among the plurality of sub-pixels in a first directionwithin a same pixel is smaller than intervals among the plurality ofpixels in the first direction, and the at least two via holes are withinthe intervals among the plurality of pixels, respectively.

Optionally, each of the plurality of pixels comprises a blue sub-pixel,a red sub-pixel, and a green sub-pixel, and an interval between the bluesub-pixel and the red sub-pixel is smaller than an interval between thered sub-pixel and the green sub-pixel.

Optionally, the isolation layer is a capping layer.

Optionally, a material of the capping layer comprises molybdenumtrioxide.

Optionally, the display substrate is an organic light emitting diodedisplay substrate, the first electrode is an anode, and the secondelectrode is a cathode.

Optionally, the second electrode is a metal electrode, the auxiliaryconductive layer is a transparent conductive layer, the isolation layeris a transparent isolation layer, and light emitted by thelight-emitting layer is emitted from one side of the second electrode.

Optionally, the auxiliary conductive layer comprises a material selectedfrom the group consisting of indium tin oxide, indium zinc oxide, indiumgallium zinc oxide and tin oxide.

One embodiment of the present disclosure is a display panel, comprisingthe display substrate according to one embodiment of the presentdisclosure.

One embodiment of the present disclosure is a display apparatuscomprising the display panel according to one embodiment of the presentdisclosure.

One embodiment of the present disclosure is a method of fabricating adisplay substrate, comprising providing a base substrate; forming aplurality of sub-pixels in an array on the base substrate, whereinadjacent sub-pixels are separated by a pixel defining layer, each of theplurality of sub-pixels includes a first electrode, a light-emittinglayer and a second electrode in a direction away from the basesubstrate, the second electrode of each of the plurality of sub-pixelsis connected to one another to form a second electrode layer; forming anisolation layer on a side of the second electrode layer opposite fromthe light-emitting layer; and forming an auxiliary conductive layer on aside of the isolation layer opposite from the second electrode layer.The isolation layer comprises at least two via holes, orthographicprojection of each of the at least two via holes on the base substratesubstantially overlaps with orthographic projection of the pixeldefining layer on the base substrate, and the auxiliary conductive layeris connected to the second electrode layer through the at least two viaholes.

Optionally, the isolation layer is formed by an evaporation technique.

Optionally, a mask comprising a plurality of opening areas and aplurality of non-opening areas is used in the evaporation technique, theisolation layer is formed on the side of the second electrode layerwithin the plurality of opening areas of the mask, and the at least twovia holes are formed on the side of the second electrode layer withinthe plurality of non-opening areas of the mask.

Optionally, the plurality of opening areas of the mask are in aone-to-one correspondence with the plurality of sub-pixels,respectively.

Optionally, orthographic projection of each of the plurality ofsub-pixels on the base substrate falls within orthographic projection ofeach of the plurality of opening areas of the mask on the basesubstrate, respectively.

Optionally, the plurality of sub-pixels constitutes a plurality ofpixels, each of the plurality of pixels comprises a blue sub-pixel, ared sub-pixel, and a green sub-pixel, and the plurality of opening areasof the mask is in a one-to-one correspondence with the plurality ofpixels, respectively.

Optionally, the auxiliary conductive layer is formed using a chemicalvapor deposition technique or a sputtering technique.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the disclosure is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the present disclosure are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1a is a schematic diagram of a driving circuit of an organic lightemitting diode display panel of the related art;

FIG. 1b is a graph of characteristic properties of a driving transistorof an organic light emitting diode display panel of the related art;

FIG. 1c is a schematic structural view of an organic light emittingdiode display substrate of the related art;

FIG. 1d is a schematic structural view of an organic light emittingdiode display substrate of the related art;

FIG. 2 is a schematic structural view of an organic light emitting diodedisplay substrate according to one embodiment of the present disclosure;

FIG. 3a is a top plan view showing arrangement of sub-pixels and anisolation layer of an organic light emitting diode display substrateaccording to one embodiment of the present disclosure;

FIG. 3b is a schematic top plan view of a mask for forming an isolationlayer of an organic light emitting diode display substrate according toone embodiment of the present disclosure;

FIG. 4a is a top plan view showing arrangement of sub-pixels of anorganic light emitting diode display substrate according to oneembodiment of the present disclosure;

FIG. 4b is a top plan view showing a mask forming an isolation layer ofan organic light emitting diode display substrate according to oneembodiment of the present disclosure; and

FIG. 4c is a top plan view showing arrangement of sub-pixels of anorganic light emitting diode display substrate according to oneembodiment of the present disclosure.

DETAILED DESCRIPTION

In order to make the objects, technical solutions, and advantages of theembodiments of the present disclosure more apparent, the technicalsolutions according to the embodiments of the present disclosure will bedescribed below clearly and fully with reference to the drawings, butthe embodiments described below are only particular embodiments, whichare not intended to represent all embodiments of the present disclosure.Based upon the embodiments in the present disclosure, other embodimentswhich will be apparent to those skilled in the art are within the scopeof the present disclosure.

When an element and an embodiment of the present disclosure areintroduced, the articles “a”, “an”, “the” and “said” are intended toindicate that one or more elements are present. The terms “comprising”,“including”, “containing” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

For the purpose of surface description hereinafter, asdirection-calibrated in the accompanying drawings, the terms “above”,“below”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom” andderivatives thereof shall relate to the present disclosure. The terms“covered with”, “on top of”, “positioned on”, or “positioned on top of”mean that, for example, a first element of a first structure is on asecond element of a second structure, wherein an intermediate elementsuch as an intermediate structure may exist between the first elementand the second element. The term “contact” means that, for example, thefirst element of the first structure and the second element of thesecond structure are connected directly or indirectly, and otherelements may exist or not exist at the interface between the twoelements.

Unless otherwise defined, all the terms (including the technical andscientific terms) used herein have the same meanings as commonlyunderstood by one of ordinary skill in the art to which the presentdisclosure is directed. It is also understood that the terms such asdefined in the usual dictionary should be interpreted as having the samemeanings as the meaning in the context of the relevant technology. Theterms should not be interpreted as an idealization or as having extrememeanings, unless they are explicitly defined herein. As employed herein,the statement that two or more parts are “connected” or “coupled”together shall mean that the parts are joined together either directlyor joined through one or more intermediate parts.

In the description of the present disclosure, the terms “center,”“horizontal,” “vertical,” “length,” “width,” “thickness,” “upper,”“lower,” “front,” “back,” “left,” “right,” “top,” “bottom,” “inner,”“outer,” or the like are based on the orientation or positionalrelationship shown in the drawings. They are used merely for convenienceof description and simplifying description of the present disclosure,but not to indicate or imply that the indicated apparatus or elementmust have a specific orientation, or be constructed and operated in aspecific orientation, therefore cannot be construed as a limitation ofthe present disclosure.

In addition, the terms “first” and “second” or the like are forillustration purposes only and are not to be construed as indicating orimplying relative importance or implied reference to the quantity ofindicated technical features. Thus, features defined by the terms“first” and “second” may explicitly or implicitly include one or more ofthe features. In the description of the present disclosure, the meaningof “plural” is two or more unless otherwise specifically andspecifically defined.

A numerical range modified by “about” herein means that the upper andlower limits of the numerical range can vary by 10% thereof. A numericvalue modified by “about” herein means that the numeric value can varyby 10% thereof.

In an organic light emitting diode display panel of prior art, eachsub-pixel has a different distance from the chip. A current of a cathodeof a sub-pixel farther from the chip needs flow a long distance in thecathode layer. Since the cathode layer has a certain resistance, avoltage drop occurs. As such, a voltage difference across a source and adrain of a driving transistor of the sub-pixel farther away from thechip is smaller than a corresponding voltage difference of the sub-pixelcloser to the chip, thereby resulting in different currents in thedifferent sub-pixels under a same driving voltage. Accordingly,brightness of the organic light emitting diode display panel becomesuneven.

In an organic light emitting diode display panel, as shown in FIG. 1aand FIG. 1b , a current flowing through a light-emitting structure suchas an OLED is controlled by a driving TFT. When the voltage differenceVds between the source and the drain of the driving transistor reaches acertain value, the driving transistor operates in a saturated region,and the current Ids flowing through the source and drain is supposed tobe affected only by the gate voltage. However, in practice, the drivingtransistor is also affected by other factors such as channel modulationeffect, etc., so that even in the situation region, the current I_(ds)flowing through the source and drain is affected by the voltagedifference between the source and the drain, V_(ds).

The OLED display panel includes a plurality of sub-pixels (such asmillions of sub-pixels), wherein a cathode voltage drop of a sub-pixelfarther from the chip (IC) is greater than a cathode voltage drop of asub-pixel closer to the chip, thereby resulting in the voltagedifference V_(ds) between the source and the drain of the drivingtransistor of the sub-pixel farther away from the IC being smaller thanthe voltage difference V_(ds) between the source and the drain of thedriving transistor of the sub-pixel closer to the IC. As a result, thecurrent of the sub-pixel farther away from the IC is smaller than thecurrent of the sub-pixel closer to the IC, thereby causing difference inbrightness of the OLED display panel. That is, the uniformity ofbrightness of the OLED display panel is not good.

FIG. 1c shows an organic light emitting diode display substrate, whichadopts a top emission structure. Each sub-pixel includes alight-emitting layer 90, an anode 91 under the light-emitting layer 90,and a cathode 92 on the light-emitting layer 90. The cathodes 92 of thesub-pixels are connected to one another to form an integral cathodelayer 100, and the integral cathode layer 100 is connected to a drivingcircuit. In the top-emitting OLED display substrate, the transparentcathode 92 plays a very important role in its performance. The cathode92 has characteristics such as good electron injectability, goodelectrical conductivity, and low light absorption. The cathode 92 isusually made of a thin film metal material. A sheet resistance R of thethin film metal cathode 92 satisfies the following formula:

R=ρ/d

Wherein ρ represents the resistivity of the cathode 92, and d representsthe thickness of the cathode 92.

According to the above formula, the sheet resistance of the cathode 92can be reduced by increasing the thickness of the cathode 92. However,increasing the thickness of the cathode 92 can cause problems such as anincrease in light absorbance of the cathode 92 and a change in colorshift, thereby affecting the luminescent properties of the OLED displaysubstrate.

The sheet resistance of the cathode 92 can also be reduced by reducingthe resistivity of the cathode 92. For example, a transparent auxiliaryconductive layer 93 may be formed on the cathode 92 to be connected inparallel with the cathode 92 to reduce the resistance of the overallstructure, as shown in FIG. 1d . However, the auxiliary conductive layer93 is usually formed by a process such as sputtering or chemical vapordeposition CVD. Such a process may adversely affect the thin film metalcathode 92 and/or the light-emitting layer 90 underneath during theformation of the auxiliary conductive layer 93. For example, since theauxiliary conductive layer 93 needs to be formed under a hightemperature, the excessive high temperature may change a shape of thecathode and morphology the organic light-emitting layer, therebyaffecting the display performance of the OLED display substrate.

Some embodiments of the present disclosure provide a display substrate,as shown in FIG. 2, FIG. 3 and FIG. 4 respectively. The mask 50 in FIG.3b corresponds to the organic light-emitting diode display substrate inFIG. 3a , and the mask 50 in FIG. 4b corresponds to the organiclight-emitting diode display substrate in FIG. 4 a.

The display substrate provided by some embodiments of the presentdisclosure includes a base substrate 10 and a plurality of sub-pixels 20disposed at intervals on the base substrate. An interval 60 is presentbetween each adjacent sub-pixels 20. Each sub-pixel 20 includes a firstelectrode 21, a light-emitting layer 22, and a second electrode 23stacked in a direction away from the base substrate 10. The secondelectrode 23 of each sub-pixel 20 is integrally connected to one anotherto form a second electrode layer 123.

In some embodiments, the display substrate provided further includes aninsulating isolation layer 30 on the side of the second electrode layeropposite from the light-emitting layer 22 and an auxiliary conductivelayer 40 on the side of the isolation layer 30 opposite from the secondelectrode layer 123. The isolation layer 30 covers all the secondelectrodes 23. Furthermore, the isolation layer 30 is provided with viaholes 31 at least at some of the intervals 60 between adjacentsub-pixels. The auxiliary conductive layer 40 is connected to the secondelectrode layer 123 through the via holes 31.

In some embodiment, the isolation layer comprises at least two viaholes, orthographic projection of each of the at least two via holes onthe base substrate substantially overlaps with orthographic projectionof the pixel defining layer on the base substrate, and the auxiliaryconductive layer is connected to the second electrode layer through theat least two via holes.

In some embodiments, the at least two via holes comprises a plurality ofvia holes within some of intervals among the plurality of sub-pixels,respectively.

In some embodiment, the at least two via holes comprises a plurality ofvia holes within all of intervals among the plurality of sub-pixels,respectively, and all of the intervals among the plurality of sub-pixelsin a first direction are the same. The first direction may be a rowdirection or a column direction.

In some embodiments, the plurality of sub-pixels constitutes a pluralityof pixels, intervals among the plurality of sub-pixels in a firstdirection within a same pixel is smaller than intervals among theplurality of pixels in the first direction, and the at least two viaholes are within the intervals among the plurality of pixels,respectively. The first direction may be a row direction or a columndirection.

In some embodiment, each of the plurality of pixels comprises a bluesub-pixel, a red sub-pixel, and a green sub-pixel, and an intervalbetween the blue sub-pixel and the red sub-pixel is smaller than aninterval between the red sub-pixel and the green sub-pixel.

In some embodiments, the display substrate is an organic light-emittingdiode display substrate.

In the organic light-emitting diode display substrate, the structure inthe longitudinal direction is the base substrate 10, the first electrode21, the light-emitting layer 22, the second electrode layer, theisolation layer 30, and the auxiliary conductive layer 40. The firstelectrodes 21 and the light-emitting layers 22 of different sub-pixels20 are spaced and distributed in an array. The portion of the secondelectrode layer corresponding to each of the first electrodes 21 is thesecond electrode 23 of each of the sub-pixels 20 respectively.

In some embodiments, the insulating isolation layer 30 separates thesecond electrode 23 in each sub-pixel 20 from the auxiliary conductivelayer 40. The isolation layer 30 has via holes 31 in the intervals 60,so that the auxiliary conductive layer 40 is connected to the secondelectrode layer in the intervals 60. That is, the second electrode layerand the auxiliary conductive layer 40 are connected in parallel, therebyreducing the sheet resistance of the overall structure of the secondelectrodes 23 and the auxiliary conductive layer 40.

In the display substrate of some embodiments, the auxiliary conductivelayer 40 is connected to the second electrode layer in the intervals 60,and the auxiliary conductive layer 40 is connected in parallel with thesecond electrode layer, thereby reducing sheet resistance of the overallstructure of the second electrode layer and the auxiliary conductivelayer 40. Accordingly, the voltage drop generated by the secondelectrode layer is reduced. Since the voltage drop generated by thesecond electrode layer is reduced, the voltage of the second electrode23 of the sub-pixel 20 farther away from the power supply unit isapproximately equal to the voltage of the second electrode 23 of thesub-pixel 20 closer to the power supply unit. Accordingly, the currentin different sub-pixels 20 under the same driving voltage isapproximately the same, thereby making brightness of the display paneluniform.

In some embodiment, the insulating isolation layer 30 separates thesecond electrode 23 of each sub-pixel 20 from the auxiliary conductivelayer 40. As such, the high temperature or other factors in the processof forming the auxiliary conductive layer 40 (sputtering or chemicalvapor deposition) are prevented from adversely affecting thelight-emitting layer 22 and the second electrode 23, thereby, forexample, avoiding changing the shape of the second electrode 23 and themorphology of the light-emitting layer 22. The isolation layer 30between the sub-pixels 20 is provided with via holes 31. The secondelectrode layer located in the interval 60 may be affected by theformation process of the auxiliary conductive layer 40, but the interval60 does not emit light. Thus, even if the second electrode layer in theinterval 60 is affected, the display performance of the displaysubstrate is not affected. Accordingly, the via holes 31 located in theintervals 60 can be used as the connection structure of the auxiliaryconductive layer 40 and the second electrodes 23.

In some embodiments, the display substrate can improve the uniformity ofbrightness while maintaining the illuminating performance.

In some embodiments, the display substrate is an organic light-emittingdiode display substrate. The first electrode 21 is an anode, the secondelectrode 23 is a cathode, and the light-emitting layer 22 is an organiclight-emitting layer. In the intervals 60 between adjacent sub-pixels,the cathode is connected to the auxiliary conductive layer 40.

The light-emitting layer 22 in the organic light-emitting diode displaysubstrate is an organic light-emitting layer, and the cathode isgenerally made of aluminum or magnesium-silver alloy (AgMg). Thesestructures are easily affected by the external environment such as ahigh temperature environment, which may change the shape of the cathodeand the morphology of the organic light-emitting layer. Since thedisplay substrate of the present embodiments has the isolation layer 30,the related problem can be reduced or eliminated.

In some embodiments, the second electrode 23 is a metal electrode, theauxiliary conductive layer 40 is a transparent conductive layer, and theisolation layer 30 is a transparent isolation layer 30. As such, thelight of the light-emitting layer 22 can be emitted from one side of thesecond electrode 23. That is, the first electrode 21 is located belowthe light-emitting layer 22, the second electrode 23 is located abovethe light-emitting layer 22, and the display substrate is in a topemission mode.

Since the light emitted from the top-emitting display substrate isemitted from the top thereof, the thickness of the metal electrode(e.g., cathode) cannot be directly increased in order not to affect thelight emission. As such, a transparent auxiliary conductive layer 40 maybe provided.

In some embodiments, the isolation layer 30 has a thickness of about 10nm to about 90 nm.

The specific thickness of the isolation layer 30 can be determinedaccording to the refractive index of the material, the luminousefficiency of the sub-pixel 20 of each color, and the like. Theisolation layer 30 can effectively protect the light-emitting layer 22or other structures in the sub-pixel 20 from being affected by theprocess of forming the auxiliary conductive layer 40. Moreover, itshould be avoided that the thickness of the entire display substratebecomes too large due to the excessive thickness of the isolation layer30.

In some embodiments, the isolation layer 30 is a capping layer (CPL).The isolation layer 30 may be made of an organic or inorganic materialhaving a high refractive index such as molybdenum trioxide (MoO₃). Thus,the second electrode 23 and the isolation layer 30 may form an opticalanti-reflection film, which improves the reflectance, but not the lightabsorption, thereby improving luminosity of the di splay substrate.

By using the capping layer having via holes as the isolation layer 30,the connection structure between the auxiliary conductive layer 40 andthe cathode or the protection structure of the sub-pixel 20 can beomitted, so that the structure of the display substrate is simple,thereby reducing difficulty of the manufacturing process.

In some embodiments, the via holes 31 of the isolation layer 30 are onlyprovided within some of the intervals 60.

The connection structure between the auxiliary conductive layer 40 andthe second electrode layer does not occupy all of the intervals 60. Theconnection structures are only within some of the intervals 60,respectively. For example, as shown in FIG. 4a , every three sub-pixels20 corresponds to a single isolation layer 30, and the isolation layer30 within the intervals 60 among the three sub-pixels 20 has no viahole. Correspondingly, an via hole of the mask 50 for preparing theisolation layer 30 corresponds to three sub-pixels 20, as shown in FIG.4 b.

In some embodiments, the via hole 31 of the isolation layer 30 isdisposed within all of the intervals 60 respectively. That is, thenon-via hole region of the isolation layer 30 corresponds to each of thesub-pixels 20. The connection region of the auxiliary conductive layer40 and the second electrode layer occupies all of the intervals 60respectively, which maximizes the connection region of the auxiliaryconductive layer 40 and the second electrode layer. Thereby, theresistance of the second electrode 23 can be further reduced, and theuniformity of brightness of the display substrate can be furtherimproved. In some embodiments, as shown in FIG. 3a , the non-via holeregions of the isolation layer 30 are in one to one correspondence withthe sub-pixels 20. That is, each sub-pixel 20 corresponds to a wholepiece of an isolation layer 30. Correspondingly, each via hole of themask 50 used to prepare the isolation layer 30 corresponds to onesub-pixel 20, as shown in FIG. 3 b.

In some embodiments, the display substrate further includes: a pixeldefining layer between the respective sub-pixels 20 for spacing therespective sub-pixels 20 to avoid mutual influence of images betweenadjacent sub-pixels 20.

In some embodiments, each of the sub-pixels 20 may further include ahole transport layer, a hole blocking layer, an electron transportlayer, an electron blocking layer or other OLED pixel structures.

Some embodiments of the present disclosure further provide a method formanufacturing the display substrate of the above embodiments. Themanufacturing method may include the following steps:

Step S01 includes forming a first electrodes 21, a light-emitting layer22, and a second electrode layer on the substrate 10.

In one embodiment, the first electrodes 21, the light-emitting layer 22,and the second electrode layer are formed on the base substrate 10 by anevaporation technique, thereby forming a plurality of sub-pixels 20spaced apart.

Step S02 includes forming an isolation layer 30 on the second electrodelayer.

In one embodiment, the isolation layer 30 may be formed using anevaporation technique. The conditions for the evaporation technique arerelatively mild, and their influence on the cathode and thelight-emitting layer 22 is relatively small in the process of formingthe isolation layer 30. The isolation layer 30 is suitably formed by anevaporation technique.

In some embodiments, a mask 50 (FMM) is employed in the evaporationtechnique to form a pattern of the isolation layer 30. Wherein, beforeforming the isolation layer 30 by the evaporation technique, a mask 50is covered on the second electrode layer, so that the formed isolationlayer 30 cannot completely cover the second electrode layer. That is,the formed isolation layer 30 is provided with via holes 31 within atleast some of the intervals 60. For example, the sub-pixels 20 of thedisplay substrate are arranged as shown in FIG. 3a , and the mask 50forming the isolation layer 30 corresponding thereto is as shown in FIG.3b . Each of the sub-pixels 20 corresponds to an opening area of themask 50. The via hole 31 of the isolation layer 30 is formed at thenon-opening area of the mask 50.

In some embodiments, the opening area of the mask 50 is larger than thearea of the sub-pixel 20 due to the alignment error of the screen of themask 50 and the evaporation shadow, etc., thereby ensuring that theisolation layer 30 can completely cover the sub-pixels 20. Of course,the opening area of the mask 50 cannot be too large. Since the mask 50has an evaporation shadow, if the opening area is too large, anisolation layer 30 may be formed within the intervals 60 betweenadjacent sub-pixels 20, thereby being disadvantageous to formation ofthe via holes 31 of the isolation layer 30.

In some embodiments, the sub-pixels 20 of the display substrate arearranged as shown in FIG. 4a , and the mask 50 forming the isolationlayer 30 corresponding thereto is as shown in FIG. 4b . Each openingarea of the mask 50 corresponds to three subpixels 20 separated withsmall intervals.

In some embodiments, as shown in FIG. 4c the plurality of sub-pixelsconstitutes a plurality of pixels 11, each of the plurality of pixelscomprises a blue sub-pixel 12, a red sub-pixel 13, and a green sub-pixel14, and the plurality of opening areas of the mask is in a one-to-onecorrespondence with the plurality of pixels, respectively.

Step S03 includes forming an auxiliary conductive layer 40.

In one embodiment, the auxiliary conductive layer 40 is formed by achemical vapor deposition (CVD) or a sputtering technique.

The chemical vapor deposition or sputtering technique is usuallyperformed under a high temperature environment, so that the influence offorming the auxiliary conductive layer 40 on the cathode and thelight-emitting layer 22 may be relatively large. The display substrateof the embodiment of the present disclosure may avoid the adverse effectof the chemical vapor deposition or sputtering technique on the cathodeand the light-emitting layer due to the presence of the isolation layer30.

The auxiliary conductive layer 40 may be formed of a material such asindium tin oxide, indium zinc oxide, indium gallium zinc oxide or tinoxide.

Some embodiments of the present disclosure further provide a displaypanel, including the display substrate of any of the above embodiments.

It is easy to understand that the display panel may further include astructure such as a driving circuit. The driving circuit may beelectrically connected to the second electrode layer. The power supplyunit may be a chip electrically connected to the second electrode layer.

Specifically, the display panel can be any product or component withdisplay function such as electronic paper, mobile phone, tabletcomputer, television, display, notebook computer, digital photo frame,navigator, and the like.

The principles and the embodiments of the present disclosure are setforth in the specification. The description of the embodiments of thepresent disclosure is only used to help understand the apparatus andmethod of the present disclosure and the core idea thereof. Meanwhile,for a person of ordinary skill in the art, the disclosure relates to thescope of the disclosure, and the technical scheme is not limited to thespecific combination of the technical features, but also covers othertechnical schemes which are formed by combining the technical featuresor the equivalent features of the technical features without departingfrom the inventive concept. For example, a technical scheme may beobtained by replacing the features described above as disclosed in thisdisclosure (but not limited to) with similar features.

1. A display substrate, comprising: a base substrate; a plurality ofsub-pixels in an array on the base substrate, wherein adjacentsub-pixels are separated by a pixel defining layer, each of theplurality of sub-pixels includes a first electrode, a light-emittinglayer and a second electrode in a direction away from the basesubstrate, the second electrode of each of the plurality of sub-pixelsis connected to one another to form a second electrode layer; anisolation layer on a side of the second electrode layer opposite fromthe light-emitting layer; and an auxiliary conductive layer on a side ofthe isolation layer opposite from the second electrode layer, whereinthe isolation layer comprises at least two via holes, orthographicprojection of each of the at least two via holes on the base substratesubstantially overlaps with orthographic projection of the pixeldefining layer on the base substrate, and the auxiliary conductive layeris connected to the second electrode layer through the at least two viaholes.
 2. The display substrate of claim 1, wherein a thickness of theisolation layer is in a range from about 10 nm to about 90 nm.
 3. Thedisplay substrate of claim 1, wherein the at least two via holescomprises a plurality of via holes within some of intervals among theplurality of sub-pixels, respectively.
 4. The display substrate of claim1, wherein the at least two via holes comprises a plurality of via holeswithin all of intervals among the plurality of sub-pixels, respectively,and all of the intervals among the plurality of sub-pixels in a firstdirection are the same.
 5. The display substrate of claim 1, wherein theplurality of sub-pixels constitutes a plurality of pixels, intervalsamong the plurality of sub-pixels in a first direction within a samepixel is smaller than intervals among the plurality of pixels in thefirst direction, and the at least two via holes are within the intervalsamong the plurality of pixels, respectively.
 6. The display substrate ofclaim 5, wherein each of the plurality of pixels comprises a bluesub-pixel, a red sub-pixel, and a green sub-pixel, and an intervalbetween the blue sub-pixel and the red sub-pixel is smaller than aninterval between the red sub-pixel and the green sub-pixel.
 7. Thedisplay substrate of claim 1, wherein the isolation layer is a cappinglayer.
 8. The display substrate of claim 7, wherein a material of thecapping layer comprises molybdenum trioxide.
 9. The display substrate ofclaim 1, wherein the display substrate is an organic light emittingdiode display substrate, the first electrode is an anode, and the secondelectrode is a cathode.
 10. The display substrate of claim 1, whereinthe second electrode is a metal electrode, the auxiliary conductivelayer is a transparent conductive layer, the isolation layer is atransparent isolation layer, and light emitted by the light-emittinglayer is emitted from one side of the second electrode.
 11. The displaysubstrate of claim 1, wherein the auxiliary conductive layer comprises amaterial selected from the group consisting of indium tin oxide, indiumzinc oxide, indium gallium zinc oxide and tin oxide.
 12. A displaypanel, comprising the display substrate according to claim
 1. 13. Adisplay apparatus comprising the display panel of claim
 12. 14. A methodof fabricating a display substrate, comprising: providing a basesubstrate; forming a plurality of sub-pixels in an array on the basesubstrate, wherein adjacent sub-pixels are separated by a pixel defininglayer, each of the plurality of sub-pixels includes a first electrode, alight-emitting layer and a second electrode in a direction away from thebase substrate, the second electrode of each of the plurality ofsub-pixels is connected to one another to form a second electrode layer;forming an isolation layer on a side of the second electrode layeropposite from the light-emitting layer; and forming an auxiliaryconductive layer on a side of the isolation layer opposite from thesecond electrode layer; wherein the isolation layer comprises at leasttwo via holes, orthographic projection of each of the at least two viaholes on the base substrate substantially overlaps with orthographicprojection of the pixel defining layer on the base substrate, and theauxiliary conductive layer is connected to the second electrode layerthrough the at least two via holes.
 15. The method of fabricating thedisplay substrate of claim 14, wherein the isolation layer is formed byan evaporation technique.
 16. The method of fabricating the displaysubstrate of claim 15, wherein a mask comprising a plurality of openingareas and a plurality of non-opening areas is used in the evaporationtechnique, the isolation layer is formed on the side of the secondelectrode layer within the plurality of opening areas of the mask, andthe at least two via holes are formed on the side of the secondelectrode layer within the plurality of non-opening areas of the mask.17. The method of fabricating the display substrate of claim 16, whereinthe plurality of opening areas of the mask are in a one-to-onecorrespondence with the plurality of sub-pixels, respectively.
 18. Themethod of fabricating the display substrate of claim 17, whereinorthographic projection of each of the plurality of sub-pixels on thebase substrate falls within orthographic projection of each of theplurality of opening areas of the mask on the base substrate,respectively.
 19. The method of fabricating the display substrate ofclaim 16, wherein the plurality of sub-pixels constitutes a plurality ofpixels, each of the plurality of pixels comprises a blue sub-pixel, ared sub-pixel, and a green sub-pixel, and wherein the plurality ofopening areas of the mask is in a one-to-one correspondence with theplurality of pixels, respectively.
 20. The method of fabricating thedisplay substrate of claim 14, wherein the auxiliary conductive layer isformed using a chemical vapor deposition technique or a sputteringtechnique.